In known rails of the aforementioned kind, the shape of the characteristic curve resulting from the presence of the elastic intermediate layer when the rail is under load is solely determined by the characteristics of the material of the elastic intermediate layer. This is particularly disadvantageous in a rail with standard rail profile (U.S. Pat. No. 3,525,472), because here the angle formed by the lateral limiting surfaces of the rail below the rail head with the vertical is very large in the upper segment and very small in the lower segment, so that when the characteristic curve for the vertical load of the rail is correctly established, the elastic intermediate layers are too hard for the horizontally occurring load, while when the characteristic curve for the horizontal load of the rail is correctly established, the elastic intermediate layers are too soft for the vertical load. Therefore, in practice there is always a compromise solution, which does not offer an optimal shape of the characteristic curve in any load direction. In a rail of this type, the sound attenuation is extraordinarily low.
An improved sound damping is achieved with another known rail, wherein in the area of the rail web a rectilinearly downward tapering area is provided, over which the rail abuts against a frame via elastic intermediate layers, the inner lateral surfaces of the frame running also rectilinearly (DE-OS 35 40 128). In this rail, the lateral surfaces limiting the rail below the rail head, as well as the inner lateral surfaces limiting the frame form respectively only one angle with the vertical. This allows for a more correct setting of the characteristic curve.